Exposure apparatus, maintenance method therefor, semiconductor device manufacturing method, and semiconductor manufacturing factory

ABSTRACT

A scanning exposure apparatus for exposing a substrate to a pattern includes an exposure system which exposes the substrate to the pattern with respect to a unit region of the substrate to which the pattern is transferred, a determination system which determines whether a condition of an exposure performed by the exposure system is allowable during the exposure, and a control system which causes the exposure system to continue exposing a remaining region in the unit region of the substrate to the pattern, even after the determination system makes a negative determination for the unit region.

This application is a divisional application of U.S. patent applicationSer. No. 09/858,964, filed May 17, 2001, now U.S. Pat. No. 6,657,703.

FIELD OF THE INVENTION

The present invention relates to an exposure apparatus used forphotolithography in the manufacturing process of a semiconductorintegrated circuit, liquid crystal display element, or the like, amaintenance method therefor, a semiconductor device manufacturingmethod, and a semiconductor manufacturing factory.

BACKGROUND OF THE INVENTION

FIG. 13 is a flow chart showing the focus algorithm of a stationaryexposure apparatus (stepper). A focus on a wafer as a substrate loadedonto a wafer stage is measured at a focus measurement shot out ofseveral representative shots on the wafer (step 1301). A globalapproximate plane as a linear plane which represents the wafer surfaceis calculated by, e.g., least-square approximation from the obtainedfocus measurement data (step 1302). The target value of the wafer stagein the Z direction when the wafer stage is driven to locate the wafersurface on the global approximate plane is called a global focus targetvalue, and its target values in the ωx and ωy directions at this timeare called global tilt target values.

Shots subjected to global focus/tilt measurement simultaneously undergoalignment measurement at, e.g., alignment mark positions (1401 x, 1401y, 1402 x, 1402 y, 1403 x, 1403 y, 1404 x, and 1404 y) of shots hatchedon the wafer in FIG. 14. FIG. 14 is a view showing a shot position onthe wafer subjected to global focus measurement. To increase theprecision of the measured global tilt amount and that of the rotationangle in the θ direction in global alignment, measurement spans in the Xand Y directions are preferably widened, and the shots are desirablynear the periphery of the wafer.

In FIG. 13, an X-Y stage moves stepwise to a target exposure shotposition (step 1303). At the same time, a Z tilt wafer stage moves to afocus/tilt position in the exposure shot that is estimated from theglobal approximate plane (step 1304). Upon the completion of movement, afocus is measured again at the exposure position (step 1305). Focusingdriving (step 1307) and focus measurement (step 1305) are repeated untilthe focus tolerance check passes (step 1306). In focus measurement (step1305), a focus sensor measures focus measurement points in a pluralityof exposure shots as shown in FIG. 15, and a linear approximate planeobtained from the measurement values is set as a wafer surface. Waferstage target values for performing focusing so as to locate the wafersurface on an image plane are sequentially calculated. FIG. 15 is a viewshowing the layout of focus measurement points within an exposure shotin the stationary exposure apparatus.

In FIG. 15, ch1 to ch5 are focus measurement points, one measurementpoint is formed from five marks (1501 a to 1501 e), and the average ofthe measurement values of the respective marks in the focus direction isused as focus measurement data for each point (ch1 to ch5). An exposureshot 1502 is measured at a plurality of focus measurement points (ch1 toch5). For example, when the focus measurement value of ch5 greatlydeviates from those of ch1 to ch4, the wafer surface is regarded to havea defect and is not exposed (case A). Alternatively, as for a greatlydifferent measurement point, its measurement value is not used as focusmeasurement data, and an approximate plane is calculated from theremaining focus measurement points (case B).

If the focus tolerance passes, the flow waits for convergence ofresidual vibrations in the X and Y directions generated in the step offocus driving/Abbe correction driving (step 1307) in FIG. 13 (step1308), and exposure starts (step 1309). In step 1310, whether all theshots have undergone the exposure sequence is checked. If N in step1310, the focus algorithm (steps 1303 to 1310) is repeated by using thefirst measured global approximate plane data (step 1302).

The surface of a process wafer may be corrugated by about 5 to 10 [μm]during the manufacturing process. When such a wafer is to be exposed,the exposure sequence is interrupted at the shot of a corrugatedportion, and the shot does not allow exposure in a prior art like caseA. In this case, in the prior art, the exposure sequence shifts toprocess the next shot without exposing the shot of a projecting portion.At the unexposed shot, the residual resist amount is larger than that atperipheral shots in the resist developing process, and may adverselyaffect a resist image at the peripheral shots.

If a focus error is generated by a wafer, the job aborts in the priorart, and the exposure sequence enters a manual operation mode where theoperator determines processing of the defective shot.

If a focusing error is generated under the influence of dust or the likeattached to a wafer chuck, the chuck must be cleaned to remove itscontamination. In a prior art like case B, however, no focusing error isdetected, and the contamination of the wafer chuck must be estimatedfrom the wafer developing result.

SUMMARY OF THE INVENTION

The present invention has been made to overcome the conventionaldrawbacks, and has as its object to provide an exposure apparatus whichminimizes the influence of a defective shot on peripheral shots, reducesdefective shots, reduces misoperations caused by the operator, anddetects contamination of a wafer chuck within the exposure process. Thepresent invention also provides a maintenance method therefor, asemiconductor device manufacturing method, and a semiconductormanufacturing factory.

To overcome the above drawbacks, according to the first aspect of thepresent invention, there is provided an exposure apparatus which has astage for aligning a substrate surface to an imaging plane on the basisof a detection signal from a focus sensor, moves the substrate by thestage, transfers a projection pattern, and exposes the substrate,comprising a controller for, when an exposure shot region on thesubstrate cannot converge to a predetermined precision, determining theexposure shot as an error, and controlling the stage so as to move thesubstrate to a predetermined position upon determination of the error,and an exposure unit for forcibly transferring the projection patternonto the substrate at the predetermined position in the exposure shotand exposing the substrate.

According to the second aspect of the present invention, there isprovided an exposure apparatus for transferring a projection patternonto a substrate and exposing the substrate while scanning the substrateby a stage, comprising a controller for, when an exposure shot region onthe substrate cannot converge during scan to a predetermined focusprecision or leveling precision, a predetermined two-dimensional synccontrol precision, or a predetermined exposure amount control precision,determining the exposure shot as an error, and controlling the stage soas to move the substrate to a predetermined position upon determinationof the error, and an exposure unit for forcibly transferring theprojection pattern onto the substrate at the predetermined position inthe exposure shot and exposing the substrate.

According to the third aspect of the present invention, there isprovided an exposure apparatus for transferring a projection patternonto a substrate and exposing the substrate while scanning thesubstrate, comprising a controller for, when an exposure shot regioncannot converge to a predetermined focus precision during scan,determining the exposure shot as an error, and controlling a shot beamfrom an exposure light source upon determination of the error.

According to the present invention, there is provided a semiconductordevice manufacturing method comprising the steps of installingmanufacturing apparatuses, for performing various processes, includingany one of the above-described exposure apparatuses, in a semiconductormanufacturing factory, and manufacturing a semiconductor device by usingthe manufacturing apparatuses in a plurality of processes.

According to the present invention, there is provided a semiconductormanufacturing factory comprising manufacturing apparatuses, forperforming various processes, including any one of the above-describedexposure apparatuses, a local area network for connecting themanufacturing apparatuses, and a gateway which allows the local areanetwork to access an external network outside the factory, whereininformation about at least one of the manufacturing apparatuses can becommunicated.

According to the present invention, there is provided a maintenancemethod for any one of the above-described exposure apparatuses that isinstalled in a semiconductor manufacturing factory, comprising the stepsof causing a vendor or user of the exposure apparatus to provide amaintenance database connected to an external network of thesemiconductor manufacturing factory, authorizing access from thesemiconductor manufacturing factory to the maintenance database via theexternal network, and transmitting maintenance information accumulatedin the maintenance database to the semiconductor manufacturing factoryvia the external network.

According to the fourth aspect of the present invention, any one of theabove-described exposure apparatuses further comprises a display, anetwork interface, and a computer for executing network software, andmaintenance information of the exposure apparatus can be communicatedvia the computer network.

Other objects and advantages besides those discussed above shall beapparent to those skilled in the art from the description of a preferredembodiment of the invention which follows. In the description, referenceis made to accompanying drawings, which form a part thereof, and whichillustrate an example of the invention. Such an example, however, is notexhaustive of the various embodiments of the invention, and, therefore,reference is made to the claims which follow the description fordetermining the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the hardware arrangement of anexposure apparatus according to an embodiment of the present invention;

FIG. 2 is a view showing a state when a wafer surface is driven to aglobal tilt plane;

FIG. 3 is a view showing the positional relationship between an exposureslit and focus measurement points on the imaging plane in the exposureapparatus according to the embodiment of the present invention;

FIG. 4 is a flow chart showing an example of an exposure sequence in theexposure apparatus according to the embodiment of the present invention;

FIG. 5 is a view showing the layout of focus measurement positions andan exposure slit within an exposure shot;

FIG. 6 is a view showing an example of operation buttons displayed upongeneration of a focus control error in the exposure apparatus accordingto the embodiment of the present invention;

FIG. 7 is a view showing an example of the user interface window of theexposure apparatus according to the embodiment of the present invention;

FIG. 8 is a view showing the concept of a semiconductor deviceproduction system including the exposure apparatus according to theembodiment of the present invention when viewed from a given angle;

FIG. 9 is a view showing the concept of the semiconductor deviceproduction system including the exposure apparatus according to theembodiment of the present invention when viewed from another givenangle;

FIG. 10 is a view showing an example of a user interface in thesemiconductor device production system including the exposure apparatusaccording to the embodiment of the present invention;

FIG. 11 is a flow chart for explaining the flow of a devicemanufacturing process by the exposure apparatus according to theembodiment of the present invention;

FIG. 12 is a flow chart for explaining a wafer process by the exposureapparatus according to the embodiment of the present invention;

FIG. 13 is a flow chart showing the focus (exposure) algorithm of aconventional stationary exposure apparatus;

FIG. 14 is a view showing a shot position on a wafer subjected to globalfocus measurement in the conventional stationary exposure apparatus; and

FIG. 15 is a view showing the layout of focus measurement points withinan exposure shot in the conventional stationary exposure apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail below with reference to the accompanying drawings.

[Exposure Apparatus]

FIG. 1 shows the hardware arrangement of an exposure apparatus accordingto an embodiment of the present invention. A reticle 109 set on areticle stage 108 is scanned at a constant speed in the directionindicated by an arrow in FIG. 1 under the control of a reticle stagecontroller 103. Part of a pattern image on the reticle 109 serving as amaster is horizontally reversed by a projection optical system 110 andprojected onto an imaging plane on a focus stage 112. The focus stage112 is mounted on an alignment stage 113 and performs alignment in the Zdirection and tilt directions (ωx and ωy). The alignment stage 113 isdrivable in the X, Y, and θ directions and is scanned at a constantspeed by a wafer stage controller 101 in the direction indicated by anarrow in FIG. 1, i.e., a direction opposite to the driving direction ofthe reticle stage 108 during scan exposure. The ratio of the scan speedsof the alignment stage 113 and reticle stage 108 is determined from theprojection magnification of the projection optical system 110 and thescaling ratio of a transferred image.

A focus measurement sensor 111 as a focus detection mechanism is fixedto an apparatus housing which contains the projection optical system110, and measures the focus direction of a wafer 120 serving as asubstrate set on the focus stage 112. A signal obtained by the focusmeasurement sensor 111 is converted into a focus measurement value 105of an expression corresponding to the coordinate system of the waferstage by a focus signal processing unit 102, and the focus measurementvalue 105 is transferred to the wafer stage controller 101. In shotexposure, the wafer stage controller 101 controls the manipulationquantity of the focus stage 112 so as to allow the surface of the wafer120 to reach a focus target value corresponding to an imaging planeincluded in the argument of an exposure command 107 transferred from amain sequence controller 104 in advance.

Reference numeral 115 denotes an illumination optical system whichdisperses the coherence of an exposure laser beam from a pulse lasersource 116 and shapes the light quantity distribution of a slit shape.The wafer stage controller 101 controls in real time the emission startand stop timings of a pulse laser by using an emission enable signal 117in accordance with the stage position during scan.

The main sequence controller 104 designates to the alignment stage 113by using the exposure command 107 a scan driving target value includedin a command issued for each shot, and designates to the focus stage 112a focus target value to an imaging plane and an initial focus targetvalue (to be referred to as a neighboring focus target valuehereinafter) for performing preset before scan exposure. The mainsequence controller 104 sends a pulse energy/wavelength command signal118 to the pulse laser source 116 for each shot or every predeterminedtiming. After one shot is exposed, a focus control target value 106 ofthe focus stage 112 calculated by the wafer stage controller 101 is sentback to the main sequence controller 104 in order to achieve alignmentin the focus direction of the shot. This data is used as the neighboringfocus target value of a subsequent shot. The neighboring focus targetvalue is used as the target value of the focus/tilt axis of the waferstage in executing forced exposure (to be described with reference to aflow chart) when the wafer 120 is so corrugated as to generate afocusing error at the next exposure shot. When the focusing error shotis the first exposure shot on the wafer 120, a global tilt target value(to be described later) is used as the target value of the focus/tiltaxis of the wafer stage in executing forced exposure.

FIG. 2 is a view showing a state after the wafer stage is driven to aposition where the global approximate plane is measured as(Z,ωx,ωy)=(0,0,0) when the next global focus/tilt measurement issimilarly done by using a value obtained by global focus/tiltmeasurement. In FIG. 2, the same reference numerals as in FIG. 1 denotethe same parts.

The surface of the wafer 120 is parallel to a driving locus (wafer stagetraveling surface 201) with a constant target value in the Z directionof the wafer stage. As far as the surface of the wafer 120 is ideallyparallel, no defocus occurs below an exposure slit in scan exposure inthis stage. In practice, however, local corrugations exist on thesurface of the wafer 120 to a considerable amount with respect to thedepth of focus. Thus, focus is measured during exposure, and a lasermust be focused not to defocus the surface of the wafer 120 immediatelybelow the slit. This amount is 3 to 4 at a maximum with respect to theglobal tilt plane on a general single-side-polished wafer 120, thoughthe amount changes depending on the surface polishing step or process ofthe wafer 120. To the contrary, the focus control precision assigned tofocus control in exposure is about 0.1 according to the 0.15 μm L/Srule.

FIG. 3 shows the positional relationship between an exposure slit andfocus measurement points on the imaging plane in the exposure apparatusaccording to the embodiment of the present invention. When the alignmentstage 113 (FIG. 2) scans the wafer in the direction indicated by arrow1, focus measurement points a, b, and c are used, and when the alignmentstage 113 scans the wafer in the direction indicated by arrow 2, focusmeasurement points A, B, and C are used. A focus measurement point S isalso set at the center of the shot. Focus is measured at combined points(a, b, c, S) and (A, B, C, S) during one cycle of a plurality of focusmeasurement events during a scan in order to confirm a convergenceresult in the focus direction during exposure. In the focus measurementcycle, an obtained focus measurement value is determined as a focusconvergence error under the following conditions (when convergencewithin a given focus alignment precision fails).

(i) Variations in measurement values from the average of measurementvalues at a, b, and c exceed a prescribed allowable amount.

(ii) An absolute tilt amount calculated from ωy=(a−c)/L exceeds aprescribed allowable amount.

(iii) An absolute focus amount calculated from Z=(a+b+c)/3 exceeds aprescribed allowable amount.

(iv) The differences between Z and ωy obtained by previous focusmeasurement, and Z and ωy obtained by current focus measurement exceedprescribed allowable amounts, respectively.

The focus convergence error occurs in the following two cases (A) and(B).

(A) A convergence error (non-exposure focus error) before exposurestarts because an exposure shot is measured for a focus measurementpoint but the exposure slit does not enter the exposure area.

(B) A convergence error (exposure abort focus error) when the exposureslit enters the exposure area and exposure already starts.

In case (A), the emission enable signal 117 in FIG. 1 is immediatelydisabled to stop emission of the pulse laser source 116 (shield anexposure beam). In a slow light source system such as a mercury lamplight source, a high-speed shutter may be arranged in the illuminationoptical system 115 to shield an exposure beam.

In case (B), exposure can be immediately stopped, like case (A), whichproduces an exposed portion and an unexposed portion within a shot. Whenexposure intermittently aborts within a shot, a portion where exposurehas aborted is stored in the wafer stage controller 101 in FIG. 1, andemission of the illumination optical system 115 starts in a retry modeat the portion where exposure was aborted. In this embodiment, exposuredoes not abort in such a case for the sake of descriptive simplicity,and exposure continues to the final portion left in the shot region byforcibly exposing the shot. At this time, exposure must continue withoutany focus measurement value. The values Z and ωy (focus and tiltpositions) at the final focus measurement position measured normally aremost desirably used. A global focus measurement value or the neighboringfocus value of a previous shot may be used.

Also, in a stationary exposure apparatus, a focus control error occurswhen, for example, the focus tolerance check does not pass (step 1306)even if the convergence loop for performing focus measurement (step1305), focus tolerance check (step 1306), and focus driving/Abbecorrection driving (step 1307) is repeated a predetermined number oftimes in the flow chart of the prior art in FIG. 13, or when thevariance of measurement values at respective measurement points from alinear approximation plane calculated between focus measurement pointsin a shot shown in FIG. 15 exceeds a prescribed amount.

FIG. 4 shows an example of an exposure sequence in the exposureapparatus according to the embodiment of the present invention. Acommand to a light source upon generation of a focus control(convergence) error is determined, and emission of the exposure lightsource is controlled in real time by the wafer stage controller 101(FIG. 1). The wafer stage controller 101 transmits for each shot to themain sequence controller 104 (FIG. 1) a focus control error status andinformation representing whether a shot has been exposed.

The flow chart in FIG. 4 shows the sequence of the main sequencecontroller 104 performed based on information from the wafer stagecontroller 101 that is obtained for each exposure shot. Alignment of thewafer 120 on the wafer stage is measured by an alignment scope 114before the exposure sequence. After a driving target value for eachexposure shot is determined, the main sequence controller 104 entersthis sequence.

In FIG. 4, if an exposure command 401 for each shot is received, thewafer stage and reticle stage temporarily skip to a pre-scan startpoint, and scan starts. During scan, a focus measurement unitsequentially measures a focus from 507 to 501 in FIG. 5, and calculatesthe target value of the wafer stage from the measurement results. FIG. 5is a view showing the layout of focus measurement positions and anexposure slit 301 (FIG. 3) within an exposure shot 508.

Processing when a focus control error occurs will be explained withreference to FIG. 4.

In FIG. 4, the focus measurement points a, b, and c (FIG. 5) are setbefore the exposure slit 301 (FIG. 5) in the scan direction, so that afocus control error (focus convergence error) 402 may occur before orduring exposure. At this time, the exposure apparatus immediatelydisplays, e.g., a message window on a user interface to display an errormessage (403).

For a focus convergence error, whether the target shot has already beenexposed is determined (404), and if the target shot has already beenexposed, the flow shifts to a sequence 405 of determining whether thecurrent mode is an automatic continuation mode. If the focus controlerror 402 occurs, whether the exposure slit 301 (FIG. 5) enters theexposure area and exposure starts is checked. If exposure does notstart, processing of inhibiting emission of the pulse light source isimmediately executed; if exposure starts, the target shot is completelyexposed without stopping emission of the light source. If the targetshot is not exposed or a focus control error is generated by a factorsuch as a disturbance from a floor, retry of the same exposure maysucceed.

In a sequence 406, whether an automatic operation mode is set isdetermined. If Yes in sequence 406, the shot (focus convergence errorshot) is exposed under the same conditions. In step 407, whether a focuscontrol error occurs even upon retry in the same shot is checked. Ifretry fails once, a forced exposure sequence 417 is executed. In forcedexposure 417, not a value obtained by measuring the wafer surface, but aglobal focus/tilt target value which is a target value independent of afocus measurement sensor value, or the focus/tilt target value of thewafer stage obtained during the exposure time of the final portion ofthe previously exposed shot is adopted as a fixed target value duringscan. In automatic forced exposure 417, even if the reliability of thefocus measurement value degrades owing to, e.g., a fault of the focusmeasurement system, the exposure sequence continues with an improperfocus/tilt target value. Forced exposure 417 should, therefore, belimited within a finite number of successive shots. In a sequence 413,if the result of counting the number of successive operations of forcedexposure 417 exceeds five shots, the job stops even in the automaticcontinuation mode (sequence stop 414).

If the job stops, buttons as shown in FIG. 6 are displayed on the userinterface in order to cause the operator to select (determine)subsequenct processing, and the flow waits for operator designation(sequence 415). FIG. 6 is a view showing an example of operation buttonsdisplayed upon generation of a focus control error in the embodiment ofthe present invention. In FIGS. 4 and 6, a CONT (Continue) button is fordesignating continuation of processing. If the operator clicks the CONTbutton, exposure of a shot suffering a focus convergence error isskipped, and the flow advances to the exposure sequence of the next shot(shot B scan exposure command 416). An ABORT (Abort) button means theend of the exposure job (411), and is for aborting the job in progressand recovering all wafers in process. An RW (Reject Wafer) button is foraborting the exposure sequence of only the current exposure target waferand recovering the wafer (412). If No in sequence 406, the jobimmediately aborts (sequence stop 408), and the flow waits for a userbutton input shown in FIG. 6 (409). Choices in this case are a sequence415, a RETRY (Retry) button for performing retry processing for a shotsuffering a focus control error, and a FORCE (Force) button forperforming forced exposure processing 410 when focusing fails.

When a focus control error is generated by the wafer stage controller101 (FIG. 1) and part of the target shot has already been exposed, theshot has already been exposed in a defocused state. If Y in the sequence405 (automatic continuation mode), a check in the sequence 413 isperformed, and the flow shifts to processing 416 of the next shot; if N,the exposure sequence aborts (sequence stop 414), and the flow waits fora user button input (415).

The position of the shot suffering the focus control error is stored inthe main sequence controller 104 (FIG. 1). The generation factors offocus control errors are classified into (A) defects of the wafersurface state, (B) contamination of the wafer chuck surface by a resistpeeled from a wafer, (C) vibrations by a disturbance from a floor, and(D) apparatus faults. Among them all, factor (B) can be separated fromthe cause because focus control errors occur at the same shot positioncommonly to respective wafers. This embodiment has a function of storinga shot position where focus control errors occur on respective wafers,regarding the focus control errors generated at the same shot positionas errors generated by contamination of the wafer chuck, and abortingthe job. When contamination of the wafer chuck is detected by thisfunction, the wafer chuck can be exchanged or cleaned to rapidlydetermine the factor of a focus control error and increase the shotyield.

As for a function of comparing the number of forcedly exposed shots inthe automatic continuation modes 405, 406, and 413 with a predeterminednumber of shots (five shots), selection of execution/non-execution ofthe automatic continuation mode and designation of a predeterminednumber of shots can be achieved via a man-machine interface connected tothe main sequence controller 104 (FIG. 1). By applying the presentinvention, it can also be easily realized to record the total number ofshots subjected to forced exposure processing for each wafer or lot andtransmit the total number to an on-line host machine. When, for example,contamination of the wafer chuck is identified, the operator can bewarned of this via the man-machine interface.

Further, the present invention can be applied as error processing whenthe sync control precision in the alignment direction or the totalexposure amount in the exposure slit that is calculated from a monitoredilluminance exceeds a preset allowable amount. Whether sync control orexposure amount control achieves a desired precision can be determinedonly after scan exposure starts. If emission of the exposure lightsource stops because the desired precision cannot be achieved, apartially unexposed portion is formed and adversely affects peripheralshots which have normally been exposed in developing the resist. Hence,the target shot is preferably completely exposed by forced exposurewithout stopping exposure when the sync control precision or exposureamount control precision deviates from a standard precision duringexposure (to be referred to as a standard precision short errorhereinafter). The next shot is normally processed with a highpossibility for a standard precision short error generated by floorvibrations, a local factor of the wafer 120 (FIG. 1), or misfire of thepulse laser source 116 (FIG. 1) (omission of emission pulses). In manycases, a standard precision short error generated by the service life ofthe pulse laser source 116 or a fault of the exposure apparatus occursat successive shots. Thus, the algorithm of the automatic continuationmode can be similarly applied to monitoring of the exposure amountcontrol precision and sync control precision. The job can continuewithout stopping the apparatus for an inevitable standard precisionshort error caused by a local factor, resulting in high apparatusavailability. A standard precision short error generated by an apparatusfault or the like can be determined to stop the sequence with a minimumdamage by monitoring whether the error is generated at successive shots.As another method of stopping the sequence owing to repeated standardprecision short errors, the errors are identified based on the totalnumber of generated errors or the number of generated errors (generationrate) within a predetermined number of exposure shots, other thanmonitoring of errors at successive shots.

As for the sync precision specification, exposure precisionspecification, and focus/leveling precision specification of theapparatus, the guaranteed performance is generally defined by sigma. Thepresent invention is effective as a means for determining whether thestandard performance of the apparatus is actually achieved andmonitoring the standard performance during the operation of theapparatus. This is because an exposure shot which does notprobabilistically meet the standard precision necessarily exists, and ifan error is determined by giving attention to the exposure result of asingle shot, the sequence may stop even during normal operation in termsof the standard definition (sigma).

A stationary exposure apparatus adopts a sequence in which exposurestarts after the focus convergence is achieved in advance. When a focusconvergence error occurs in the focus convergence process, exposure canbe stopped before it starts by canceling emission of a light source orkeeping the shutter closed. The stationary exposure apparatus does notrequire processing 404 of determining whether part of a shot has beenexposed upon generation of a focus convergence error in FIG. 4, andprocessing 405 of determining whether the exposure apparatus operates inthe automatic continuation mode. The remaining processes can besimilarly applied as the focus control error processing step in thestationary exposure apparatus.

FIG. 7 is a view showing an example of the user interface window of theexposure apparatus according to the embodiment of the present invention.Reference numeral 740 denotes a window for displaying a sequence inprogress; 741, a window for displaying an error and warning generatedduring execution of a job; and 742, a wafer shape to be exposed, onwhich exposure shots 701 to 730 are hatched upon the completion ofexposure. Of the exposure shots 701 to 730, the exposure shots 705 and706 represent shots suffering focus control errors and are hatched in adifferent color to allow the operator to discriminate them from normallyexposed shots. Reference numeral 743 denotes an operation button. Apermitted operation changes depending on a sequence which executes ajob, and a menu displayed on the button 743 changes depending on theoperation. If a re-exposure enable focus convergence error occurs in amode other than the automatic continuation mode, operation buttons asshown in FIG. 6 are displayed to wait for operator designation.

[Embodiment of Semiconductor Production System]

A production system for a semiconductor device (e.g., a semiconductorchip such as an IC or LSI, liquid crystal panel, CCD, thin-film magnetichead, micromachine, or the like) using the exposure apparatus will beexemplified. A trouble remedy or periodic maintenance of a manufacturingapparatus installed in a semiconductor manufacturing factory, ormaintenance service such as software distribution is performed by using,e.g., a computer network outside the manufacturing factory.

FIG. 8 shows the overall system cut out at a given angle. In FIG. 8,reference numeral 801 denotes a business office of a vendor (apparatussupply manufacturer) which provides a semiconductor device manufacturingapparatus. Assumed examples of the manufacturing apparatus aresemiconductor manufacturing apparatuses for performing various processesused in a semiconductor manufacturing factory, such as pre-processapparatuses (e.g., a lithography apparatus including an exposureapparatus, a resist processing apparatus, and an etching apparatus, anannealing apparatus, a film formation apparatus, a planarizationapparatus, and the like) and post-process apparatuses (e.g., an assemblyapparatus, an inspection apparatus, and the like). The business office801 comprises a host management system 808 for providing a maintenancedatabase for the manufacturing apparatus, a plurality of operationterminal computers 810, and a LAN (Local Area Network) 809 whichconnects the host management system 808 and computers 810 to build anintranet. The host management system 808 has a gateway for connectingthe LAN 809 to Internet 805 as an external network of the businessoffice, and a security function for limiting external accesses.

Reference numerals 802 to 804 denote manufacturing factories of thesemiconductor manufacturer as users of manufacturing apparatuses. Themanufacturing factories 802 to 804 may belong to different manufacturersor the same manufacturer (pre-process factory, post-process factory, andthe like). Each of the factories 802 to 804 is equipped with a pluralityof manufacturing apparatuses 806, a LAN (Local Area Network) 811 whichconnects these apparatuses 806 to construct an intranet, and a hostmanagement system 807 serving as a monitoring apparatus for monitoringthe operation status of each manufacturing apparatus 806. The hostmanagement system 807 in each of the factories 802 to 804 has a gatewayfor connecting the LAN 811 in the factory to the Internet 805 as anexternal network of the factory. Each factory can access the hostmanagement system 808 of the vendor 801 from the LAN 811 via theInternet 805. The security function of the host management system 808authorizes access of only a limited user. More specifically, the factorynotifies the vendor via the Internet 805 of status information (e.g.,the symptom of a manufacturing apparatus in trouble) representing theoperation status of each manufacturing apparatus 806, and receivesresponse information (e.g., information designating a remedy against thetrouble, or remedy software or data) corresponding to the notification,or maintenance information such as the latest software or helpinformation. Data communication between the factories 802 to 804 and thevendor 801 and data communication via the LAN 811 in each factory adopta communication protocol (TCP/IP) generally used in the Internet.Instead of using the Internet as an external network of the factory, adedicated network (e.g., an ISDN) having high security which inhibitsaccess of a third party can be adopted. Also, the user may construct adatabase in addition to the one provided by the vendor and set thedatabase on an external network, and the host management system mayauthorize access to the database from a plurality of user factories.

FIG. 9 is a view showing the concept of the overall system of thisembodiment that is cut out at a different angle from FIG. 8. In theabove example, a plurality of user factories having manufacturingapparatuses and the management system of the manufacturing apparatusvendor are connected via an external network, and production managementof each factor or information of at least one manufacturing apparatus iscommunicated via the external network. In the example of FIG. 9, afactory having manufacturing apparatuses of a plurality of vendors andthe management systems of the vendors for these manufacturingapparatuses are connected via the external network of the factory, andmaintenance information of each manufacturing apparatus is communicated.In FIG. 9, reference numeral 901 denotes a manufacturing factory of amanufacturing apparatus user (e.g., a semiconductor device manufacturer)where manufacturing apparatuses for performing various processes, e.g.,an exposure apparatus 902, a resist processing apparatus 903, and a filmformation apparatus 904 are installed in the manufacturing line of thefactory. FIG. 9 shows only one manufacturing factory 901, but aplurality of factories are networked in practice. The respectiveapparatuses in the factory are connected to a LAN 960 to build anintranet, and a host management system 905 manages the operation of themanufacturing line. The business offices of vendors (apparatus supplymanufacturers) such as an exposure apparatus manufacturer 910, a resistprocessing apparatus manufacturer 920, and a film formation apparatusmanufacturer 930 comprise host management systems 911, 921, and 931 forexecuting remote maintenance for the supplied apparatuses. Each hostmanagement system has a maintenance database and a gateway for anexternal network, as described above. The host management system 904 formanaging the apparatuses in the manufacturing factory of the user, andthe management systems 911, 921, and 931 of the vendors for therespective apparatuses are connected via the Internet or dedicatednetwork serving as an external network 900. If a trouble occurs in anyone of a series of manufacturing apparatuses along the manufacturingline in this system, the operation of the manufacturing line stops. Thistrouble can be quickly solved by remote maintenance from the vendor ofthe apparatus in trouble via the Internet 900. This can minimize thestoppage of the manufacturing line.

Each manufacturing apparatus in the semiconductor manufacturing factorycomprises a display, a network interface, and a computer for executingnetwork access software and apparatus operating software which arestored in a storage device. The storage device is a built-in memory,hard disk, or network file server. The network access software includesa dedicated or general-purpose web browser, and provides a userinterface having a window as shown in FIG. 10 on the display. Whilereferring to this window, the operator who manages manufacturingapparatuses in each factory inputs, in input items on the windows,pieces of information such as the type of manufacturing apparatus 1001,serial number 1002, subject of trouble 1003, occurrence date 1004,degree of urgency 1005, symptom 1006, remedy 1007, and progress 1008.The pieces of input information are transmitted to the maintenancedatabase via the Internet, and appropriate maintenance information issent back from the maintenance database and displayed on the display.The user interface provided by the web browser realizes hyperlinkfunctions 1010, 1011, and 1012, as shown in FIG. 10. This allows theoperator to access detailed information of each item, receive thelatest-version software to be used for a manufacturing apparatus from asoftware library provided by a vendor, and receive an operation guide(help information) as a reference for the operator in the factory.Maintenance information provided by the maintenance database alsoincludes information concerning the present invention described above.The software library also provides the latest software for implementingthe present invention.

A semiconductor device manufacturing process using the above-describedproduction system will be explained. FIG. 11 shows the flow of the wholemanufacturing process of the semiconductor device. In step 1 (circuitdesign), a semiconductor device circuit is designed. In step 2 (maskformation), a mask having the designed circuit pattern is formed. Instep 3 (wafer manufacture), a wafer is manufactured by using a materialsuch as silicon. In step 4 (wafer process) called a pre-process, anactual circuit is formed on the wafer by lithography using a preparedmask and the wafer. Step 5 (assembly) called a post-process is the stepof forming a semiconductor chip by using the wafer manufactured in step4, and includes an assembly process (dicing and bonding) and a packagingprocess (chip encapsulation). In step 6 (inspection), inspections suchas the operation confirmation test and durability test of thesemiconductor device manufactured in step 5 are conducted. After thesesteps, the semiconductor device is completed and shipped (step 7). Forexample, the pre-process and post-process are formed in separatededicated factories, and maintenance is done for each of the factoriesby the above-described remote maintenance system. Information forproduction management and apparatus maintenance is communicated betweenthe pre-process factory and the post-process factory via the Internet ora dedicated network.

FIG. 12 shows the detailed flow of the wafer process. In step 11(oxidation), the wafer surface is oxidized. In step 12 (CVD), aninsulating film is formed on the wafer surface. In step 13 (electrodeformation), an electrode is formed on the wafer by vapor deposition. Instep 14 (ion implantation), ions are implanted in the wafer. In step 15(resist processing), a photosensitive agent is applied to the wafer. Instep 16 (exposure), the above-mentioned exposure apparatus exposes thewafer to the circuit pattern of a mask. In step 17 (developing), theexposed wafer is developed. In step 18 (etching), the resist is etchedexcept for the developed resist image. In step 19 (resist removal), anunnecessary resist after etching is removed. These steps are repeated toform multiple circuit patterns on the wafer. A manufacturing apparatusused in each step undergoes maintenance by the remote maintenancesystem, which prevents trouble in advance. Even if trouble occurs, themanufacturing apparatus can be quickly recovered. The productivity ofthe semiconductor device can be increased in comparison with the priorart.

The above-described embodiment enables forced exposure when a waferflatness defect is generated by the process. The influence on peripheralshots exposed normally in etching can be minimized to increase the waferyield.

The above-described embodiment comprises a function of storing thegeneration position of a focus control error between the wafers when awafer flatness defect is generated by the chuck. In addition to theabove effects, contamination of the wafer chuck can quickly be found.

The above-described embodiment comprises a function of stopping exposureif scan exposure does not start and retrying exposure when a focuscontrol error is generated under the influence of a disturbance from afloor. The ratio of erroneous exposure shots can be reduced to increaseyield.

Moreover, the above-described embodiment comprises a function ofautomatically determining retry or forced exposure. The stop time of theapparatus due to a wait for an operator determination can be minimizedto increase the apparatus availability.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to apprise the public of thescope of the present invention, the following claims are made.

1. A scanning exposure apparatus for exposing a substrate to a pattern,said apparatus comprising: an exposure system which exposes thesubstrate to the pattern with respect to a unit region, to which thepattern is transferred, of the substrate; a determination system whichdetermines whether a condition of an exposure performed by said exposuresystem is allowable during the exposure; and a control system whichcauses said exposure system to continue exposing a remaining region inthe unit region of the substrate to the pattern, even after saiddetermination system makes a negative determination for the unit region.2. An apparatus according to claim 1, wherein the condition of theexposure includes a position of a region of the substrate.
 3. Anapparatus according to claim 2, wherein the position is a position in adirection along which the pattern is projected.
 4. An apparatusaccording to claim 1, wherein the condition of the exposure includes aprecision of an exposure control performed by said exposure system. 5.An apparatus according to claim 4, wherein the precision of the exposurecontrol includes at least one of an alignment sync control precision andan exposure amount control precision.
 6. A device manufacturing methodcomprising: a step of exposing a substrate to a pattern using anexposure apparatus defined in claim
 1. 7. A scanning exposure apparatusfor exposing a substrate to a pattern, said apparatus comprising: anexposure system which exposes the substrate to the pattern with respectto a unit region, to which the pattern is transferred, of the substrate;a determination system which determines whether a condition of anexposure performed by said exposure system is allowable during theexposure; a control system which causes said exposure system to expose acomplete region in the unit region of the substrate to the pattern, evenif said determination system makes a negative determination for the unitregion; and a display system which discriminately displays the unitregion, for which said determination system makes the negativedetermination, of the substrate.
 8. An apparatus according to claim 5,wherein the condition of the exposure includes a position of a region ofthe substrate.
 9. An apparatus according to claim 7, wherein theposition is a position in a direction along which the pattern isprojected.
 10. An apparatus according to claim 7, wherein the conditionof the exposure includes a precision of an exposure control performed bysaid exposure system.
 11. An apparatus according to claim 10, whereinthe precision of the exposure control includes at least one of analignment sync control precision and an exposure amount controlprecision.
 12. A device manufacturing method comprising: a step ofexposing a substrate to a pattern using an exposure apparatus defined inclaim 7.